Display device



A. D. PARK DISPLAY DEVICE Nov. 14, T1939.

Filed F'eb. 19, 1958 wllll.|ll

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M01/MAMA Patented Nov. 14, 1939 UNITED STATES PATENT OFFICE DISPLAY DEVICE Application February 19, 1938, Serial No. 191,521

Claims.

This invention relates to display devices and, more particularly, to a device for conveniently and expeditiously demonstrating the efciency of sound absorbing material.

5 Considerable difficulty has been experienced in demonstrating the acoustical advantages obtainable by the use of sound absorbing material. Since the science of acoustics is a comparatively recent art, prospective users View with skepticism l0 claims regarding the advantages obtainable by the use of sound absorbing materials. A rather large investment is usually required to acoustically treat homes, factories, or oiiice buildings and it is desirable to demonstrate to a prospecl' tive user the acoustical advantages obtainable by the use of sound absorbing material since in many cases such demonstration will readily convince him of the desirability of an acoustical installation. In many cases, acoustical installations are not located within convenient distances and the prospective user is reluctant to expend the time required to inspect such installations.

The chief object of my invention is to provide a display device for conveniently demonstrating the efciency ci sound absorbing material. An object of my invention is to provide a compact, portable device which may be conveniently and expeditiously arranged to demonstrate the eniciency of sound absorbing material. A further object is to provide a light-weight, compact display device which may be easily and conveniently carried by a salesman to demonstrate the advantages of sound absorbing material.

My invention relates to a display device for demonstrating the eiciency of a sound absorbing material comprising in combination sound absorbing material forming a sound resonant chamber, sound reflecting material forming a second sound resonant chamber, and a source of sound, said resonant chambers being so arranged as to be exposed successively to sound vibrations created by the actuation of said source of sound whereby relative sound absorption of the materials forming such chambers may be demonstrated.

The accompanying drawing illustrates a preferred embodiment of my invention, in which Figure 1 is a view in elevation, partially broken away, ci the assembled device; and

Figure 2 is a view partly in elevation and partly in section of the various elements of my device before assembly.

Referring to the drawing, there is shown a tube of sound absorbing material 2 forming a sound 55 resonant chamber 3, the base of the chamber 3 being closed by a metal plate li, itsvupper end or outlet remaining open in order that sound vibrations may freely enter and leave the chamber. Sound absorbent material may be used to close the base of the chamber, if desired; `a metal plate is preferable, however, since it protects the bottom of the tube from careless or rough handling. The sound absorbing material may comprise Corkoustic and acoustical material manufactured by Armstrong Cork Company in accordance with Patent No. 2,051,628, issued August 18, 1936, in the names of Calvin N. Wenrich, Herbert Paschke and Clarence C. Vogt. While I prefer to use Corkoustic it will be understood other sound absorbent material may be used provided such material possesses sufcient structural strength to maintain its form as a tube. The walls of the tube 2 may be of any thickness sulcient to be sound absorbing; preferably, I form them approximately one inch in thickness.

A paper tube 5 may be provided surrounding and protecting the exterior walls of the tube 2. The paper tube obviates any damage to the walls of the tube 2 which may be caused by careless or rough handling of the device in use. If a tube 5 be used, preferably, the base 4 is extended to the exterior Wall of the tube as illustrated in Figure 1. The tube 5 may be adhesively secured to the plate 4 and the Walls of the tube 2, if desired.

A tube of sound reflecting material 6 such as metal, for example, brass, having a sound reso nant chamber l is dimensioned to nest within the chamber 3, the sound resonant chamber 1 having approximately the same dimensions as the chamber 3. The base 8 of the chamber 'l is closed, the upper end or outlet remaining open in order that sound vibrations may freely enter and leave the chamber. A flange 9 is provided on the upper end of the sound reiiecting tube 6 in order that it may be of the same over-all top diameter as the sound absorbent tube 2 so that conditions are approximately equal when the sound resonant chambers are exposed to sound vibrations. If a paper tube 5 be used, the diameter of the iiange is increased accordingly.

A source of sound I0, such as a tuning fork, is provided nesting within the chamber 5. Preierably, a resilient compressible stopper Il is secured to the handle of the tuning fork, the handle of such fork passing through an orice therein. Such stopper is of slightly greater diameter than the chamber 'l in order that it need be compressed to some extent when the fork is nested therein, so that its attempted expansion securely retains the fork therein.

ifi

In operating the display device, the tube 6 is removed from the tube 2 and arranged side by side therewith. It may be arranged in any desired manner provided such arrangement does not permit sound vibrations to simultaneously penetrate into the chambers 3 and l. I'he tuning fork IU is removed from the tube 6, actuated to create sound vibrations, and held successively over the tubes 2 and 6 and the difference in reenforcement of the sound vibrations due to the difference in the sound absorbing characteristics of the walls of the resonant chambers 3 and l. is noted.

The sound resonant chambers 3 and 1 are of substantially the same dimensions in order that a fair basis of comparison of the materials forming such chambers may be made. It is essential that such chambers be of such length as to be 1n resonance with sound vibrations created by the actuation of the tuning fork to demonstrate the different effects with maximum differences in audibility. Sound vibrations may be of any convenient frequency easily audible to a person of normal hearing. Preferably, I use a tuning fork having a frequency of 512 vibrations per second.

In such case, the resonant chambers may be ap proximately six inches in length, the length decreasing as the rate of vibrations increase and vice versa.

While I have described my invention with particular reference to demonstrating the eiiciency of a sound absorbing material in comparison to that of a sound reflecting material such as metal, it will be understood my invention may be carried out so as to demonstrate the relative eficiency of two different sound absorbing materials, provided such difference is sufficiently great as to be audible to the ear of the person of normal hearing.

' It will be readily seen that my invention provides a device long needed in the acoustical eld. It is inexpensive and economical to manufacture and may be used for demonstration purposes by a person relatively unskilled in the mathematical aspects of acoustics. It is of considerable value inthe sale of acoustical material since it conveniently, expeditiously and audibly demon strates the efficiency of sound absorbing material to a prospective user who would have difficulty in understanding a mathematical comparison in terms of decibels.

While I have disclosed and described a preferred embodiment of my invention it will be understood it is not to be limited thereto since it may be otherwise embodied within the scope of the following claims.

I claim:

1. In a display device for demonstrating the enciency of a sound absorbing material, the combination of sound absorbing material forming a sound resonant chamber, sound reflecting material forming a second sound resonant chamber, and a tuning fork, said resonant chambers adapted to be exposed successively to sound vibrations created b-y the actuations of said tuning fork whereby the relative diierence of sound absorption by the materials forming such chambers may be demonstrated.

2. A display device according to claim 1, in which the sound resonant chambers are of such length as to be in resonance with sound vibrations created by the tuning fork.

3. In a display device for demonstrating the efficiency of a sound absorbing material, the combination of sound absorbing material forming a sound resonant chamber, sound absorbing material of relatively less efliciency than said material forming a second sound resonant chamber, and a tuning fork, said resonant chambers adapted to be exposed successively to sound vibrations created by the actuation of said tuning fork whereby relative sound absorption of the materials forming such chambers may be demonstrated.

4. In a display device for demonstrating the efficiency of a sound absorbing material, the combination of sound absorbing material forming a sound resonant chamber, sound reflecting material forming a second sound resonant chamber,

and means for creating sound vibrations, said resonant chambers adapted to be exposed successively to sound vibrations created by the actuation of said means whereby the relative difference of sound absorption of the materials forming such chambers may be demonstrated.

5. In a display device for demonstrating the efliciency of a sound absorbing material, the combination of sound absorbing material forming a sound resonant chamber, sound absorbing material of relatively less efciency than said material forming a second sound resonant chamber. and means for creating sound Vibrations, said resonant chambers adapted to be exposed successively to sound vibrations created by the actuation of said means whereby relative sound absorption of the material forming such chambers may be demonstrated.

ARTHUR D. PARK. 

